For individuals, the cost of losing your domain is far too high if it means losing your identity on multiple services at the same time. And, if nothing else, people eventually die, so domains will be lost by their original owner and then re-used, breaking the notion of identity again in the longer run.
People keep devising more and more involved ways to maintain identities other than your legal one, but if you think about it you can still lose any of those and no one should use them for anything serious.
And if you take 1000s of judges of different ideologies who could do it, I would rather put my trust in Google that they won't mistakenly ban my account.
Entire brands are built around domain names, and even when not, they’re extremely common in advertising for most brands. To the tune of thousands or tens of thousands of dollars spent to acquire the right domain name.